Smoking causes 90% of all lung cancer deaths among men and 80% of lung cancer deaths in women. Surgery is a great opportunity to help patients quit smoking. Smokers are at increased risk for heart, lung, and wound complications around the time of surgery. Even a brief abstinence from smoking can produce benefits. Surgery can also motivate smokers to quit spontaneously. If the investigators can take advantage of this great opportunity, they may be able to help many smokers quit using simple means. However, currently most smokers continue to smoke cigarette on the morning before surgery, as shown by the measurement of exhaled carbon monoxide (CO) on the morning of surgery. CO is one of the many poisons in cigarette smoke. It only stays in the body for a few hours. By asking smokers to blow into a small machine, the investigators can test the CO level in the smokers' body and thus know if they have just smoked within the past few hours. The goal of this study is to determine the role of carbon monoxide monitoring as a means to decrease cigarette smoking before surgery. The investigators will identify a group of smokers who are scheduled for surgery and invite them to participate. One or two days before surgery, half of the patients will receive a brief advice about quit smoking. The other half of patients will be told that their CO will be checked before surgery, in addition to the brief advice. On the morning of surgery, the investigators will then check their CO level to determine if they have followed the advice. In order to have a better understanding about the factors influencing patients' intent to quit smoking, the investigators will ask all study participants to fill out a questionnaire. The questionnaire is constructed according to behavioral theories which provide good framework for studying people's intent and behavior. If the investigators are successful, they will determine how much of an impact the message of CO testing has on smoking before surgery. The investigators will also gain insights into facilitators and barriers to smoking cessation around the time of surgery. The brief intervention evaluated in this study has potential to be disseminated and to promote the long term health of surgical patients.